Grounding electrodes (or ground rods) used in conjunction with a grounding electrode conductor, are used to bond various electrically conductive pieces of equipment to the same ground potential. This accomplishes two important functions: first, for personnel and equipment safety; second, for establishing a common ground reference point for the electrical system.
Various municipalities have differing requirements for grounding installations. Many, for instance, rely upon NFPA 70, otherwise known as the National Electrical Code, while still others rely upon local or city codes. In any case, the vast majority requires the use of a grounding electrode for various installations, such as grounding an electrical service to a building, grounding the lightening protection system on a building, tying together a grounding grid utilized by some special buildings, or grounding various pieces of electrically conductive equipment that are in close proximity to an electrical potential or are at risk of coming into contact with an electrical potential.
Grounding electrodes are long (approximately 8 to 10 feet), thin rods that are driven into the earth and are intended to be connected to the system to be grounded. Generally, they are made of steel and have an outer coating of copper. They also generally have a pointed end, which is inserted into the earth, and a flat end for hammering to drive the electrode into the earth.
The problem faced by installers is that the earth may be very hard or may contain rocks, which inhibits the insertion of the grounding electrode into the earth. In addition, in the winter months, the earth may be frozen, which will further prevent installation.
Another problem faced is that the grounding electrode is between eight to ten feet long, therefore, in order to insert it into the ground, the installer must climb up on a ladder and attempt to strike the small end of the grounding electrode with a sledge hammer while maintaining a precarious balance on the ladder.
Yet another problem faced by installers is the spreading of the flat end of the grounding electrode as it is hammered into place. This is a problem because the flat end will become wider as it is continually hammered, thereby inhibiting the installation of the attachment device, typically an “acorn nut,” for clamping the grounding electrode conductor to the grounding electrode.
Still another problem associated with the installation of grounding electrodes is that due to the difficultly of installation, installers may not fully insert the grounding electrode into the earth. The remaining portion of the grounding electrode is then cut off so that the remaining end is flush with grade. Altering the grounding electrode in this manner is undesired and in some cases does not comply with state and local codes. Due to the fact that the grounding electrode is inserted into the earth, inspectors may have a difficult time trying to ascertain whether the full length of the grounding electrode was inserted into the ground or whether a portion was cut off.
There have been many attempts to overcome these problems, but none have effectively overcome them. For instance, U.S. Pat. No. 5,337,836 (“the '836 patent”) to Williams and U.S. Pat. No. 5,248,002 (“the '002 patent”) to Williams both describe a device for installing a grounding electrode. Both these devices consist of a pipe, open on one end and closed on the other, with weights attached to the closed end. The grounding electrode is hammered into place by the installer. Both the '836 and the '002 patents provide a device that will not flatten the head of the grounding electrode. However, as can be seen from the figures, installers will still need to exert a substantial force in order to hammer the grounding electrode through hard earth. In addition, these devices will be difficult to handle while balancing on a ladder due to the length of the grounding electrode.
Another attempt to overcome these problems is disclosed in U.S. Pat. No. 5,029,427 (“the '427 patent”) to Jewett and U.S. Pat. No. 5,010,710 (“the '710 patent”) to Grey et al. Both the '427 and the '10 patents disclose systems for installing grounding electrodes with a driving machine. The clamp is attached to the grounding electrode to receive the end of the hammering device. This will protect the end from flattening, however, this requires the purchase of the clamping device along with the electric or pneumatic hammering device, which may be very expensive. In addition, both the '427 and the '710 patents provide only for hammering action, and in very rocky or hard soil. This may not be enough to drive the grounding electrode into the earth.
Yet another attempt to overcome these problems is disclosed in U.S. Pat. No. 4,688,969 (“the '969 patent”) to Bruser et al. Th 69 patent discloses the use of a hollow auger bit and a shaft where the grounding electrode is received in the hollow center of the tool. The auger bit is drilled into the ground carrying the grounding electrode with it. Once the correct depth is reached, the auger bit is reversed and withdrawn, while the grounding electrode is left in the earth. The major drawback for this device is that it requires the use of very large equipment, such as an auger drill mounted to back of a utility truck, to implement. This equipment may be very expensive and cumbersome. Further, it is not clear that all municipalities would accept this installation method because the hole that is drilled for the grounding electrode is larger than the electrode, thereby creating very loose soil around it or even creating an air gap between the electrode and the earth. This will substantially decrease the effectiveness of the grounding electrode and may be unacceptable to the local authorities.